U.S. Pat. No. 3,828,780 held by the same assignee as the present disclosure has a combined electrosurgical coagulator suction instrument. That patent is incorporated herein by reference and made a part hereof. The suction electrosurgery hollow metal tube herein is an improvement in the instrument of the '780 patent.
Coagulation of blood vessels during surgery by the application of a high frequency electrical current remains a standard and widely used surgical technique. In this surgery, the tissue of the patient is electrically connected to one side of an electrosurgical circuit while an electrically conductive electrode is connected to the other. When the electrode touches or is near an operative site, a high frequency electrical current flows from the electrode. The energy coagulates at a point where the current arcs from the electrode tip to the patient's tissue.
When this technique seals blood vessels, some quantity of blood will be encountered at the precise region of coagulation. It is therefore often necessary that the excess blood be removed by a suction instrument. Similarly smoke and debris from the electrosurgery should be removed.
The conventional suction instrument takes the form of a plastic body or fitting having a passage connected to a suction source. An elongate hollow metal tube mounted in the body is inserted into the incision to suck out blood or other body fluids. The suction instrument is controlled by a simple vent in the body, the surgeon covering it with a finger when suction is desired in the hollow metal tube and uncovering the vent if suction at the hollow metal tube end is not desired.
The shape of the tip of an electrosurgical coagulator electrode is not critical. Providing an instrument capable of performing electrosurgical coagulation and suction with the hollow metal tube of electrical conductor connected to the electrosurgical coagulating power circuit have been unsatisfactory. This arrangement was unsatisfactory as blood is electrically conductive. If the surgeon places a finger over the vent to induce suction while electrical current flows through the hollow metal tube electrode, blood in the vent conducts current to the finger. The '780 patent addresses that problem as the high frequency currents employed in combination with the thin material of the surgeon's glove offer no effective resistance to the electric current.
Valleylab of Boulder Colo. has sold commercial products exactly like the disclosure of the '780 patent. The exact configuration of the plastic body or fitting thereof provides an insulated handle for the safety and convenience of the surgeon. Several difficulties in the assembly of the hollow metal tube to the plastic body require unnecessary steps and result in a less than ideal fluid tight connection therebetween. The disclosure herein addresses those difficulties with assembly method steps and instrument changes that provide a hereto unknown process for sealingly fitting the hollow metal tube into the body.